[Feline infectious peritonitis - a current overview]

Coronaviruses (CoVs) are positive, single-stranded RNA viruses that can infect various animal species as well as humans. Particularly relevant for cats is the feline coronavirus (FCoV), which is widespread in cat populations worldwide. Infection with FCoV is usually asymptomatic. However, in multi-cat households, approximately 5-12% of FCoV-infected cats develop feline infectious peritonitis (FIP) due to mutations in the spike gene. FIP is an immune-mediated disease that previously was always fatal. These mutations result in a tropism shift from enterocytes to monocytes and macrophages. The associated change in the virulence of FCoV leads to the characteristic granulomatous vasculitis and perivasculitis observed in FIP. Recently, significant advancements have been made in understanding FIP. Studies show that antiviral drugs used in human medicine, such as the nucleoside analog GS-441524, are effective against FIP and can provide affected cats with a survival chance of up to 100%. Additionally, a novel FCoV variant, FCoV-23, has been identified in cats from Cyprus. According to newest research, this virus arose through a recombination between FCoV and the highly virulent pantropic canine coronavirus; it can be directly transmitted from cat to cat and lead to FIP. Furthermore, increasing evidence suggests that FIP is frequently associated with myocarditis. This article provides an overview of the current knowledge on FIP, including its pathology, clinical signs, effective treatment options, and preventive measures.